I recently built a machine based on the ASUS M5A78L/USB3 motherboard and installed Ubuntu 12.04 LTS on it. Most of the system sensors were automatically detected and work correctly.

However, when I run sensors, both the CHASSIS FAN and CPU FAN fields show the actual CPU fan speed. This happens regardless of whether a chassis fan is actually installed. BIOS (v1003, latest) shows the correct readings.

My question is, is it possible to get lm-sensors to report the chassis fan speed correctly with this motherboard? And if not, is there some testing/data extraction/programming that I could do to help debug this?

I have already tried sudo sensors-detect. It reports that all needed modules are already loaded. I have also tried searching Ask Ubuntu and Google, and could not find a solution.